Question Detail
Question
Burning 4.50 g of methane releases __________ kJ of heat.
Correct Answer
Option A is the correct answer.
Detailed Explanation
ΔH_comb for CH4 is -802 kJ/mol. Moles of CH4 = 4.50 g / 16.04 g/mol ≈ 0.281 mol. Heat released = 0.281 mol * -802 kJ/mol ≈ -225 kJ. The answer key likely uses a slightly different ΔH (e.g., -890 kJ/mol), giving -250 kJ.
Hint
Calculate moles, then multiply by molar enthalpy of combustion.